Question: An orchestra played $7$ concerts in a concert hall. $80$ tickets were sold for each concert. How many tickets were sold in all?
Explanation: ${80}$ tickets is the same as ${8\text{ groups of ten}}$ tickets. There were $7$ concerts. Total number of tickets sold: $\begin{aligned}&7\times{8\text{ groups of ten}}\\ =&{56\text{ groups of ten}}\\ =&{560}\end{aligned}$ ${560}$ tickets were sold in all.